Labelmaster's BMP®41 Printer Cartridges can be used for a variety of applications, including wire marking, sleeving, panel labeling, terminal block, patch panel, general ID and more. The black on white tape is made of heat-shrink polyolefin, has a pressure-sensitive adhesive and good contrast, and is smear resistant. They are easy to install - just drop and lock to load. Measuring 4/17 x 3/4 in., these are sold in cartridges that contains 80 labels.